Old Navy $1 Flip Flop Sale is TOMORROW May 21st! This post may contain affiliate links. Please see the full disclosure policy here. Posted on May 20, 2011 Written by Mary Leave a Comment REMINDER FOR TOMORROW: Old Navy’s $1 Flip Flop Sale RETURNS this Saturday, May 21st! Limit 5. If you’re planning to head to Old Navy for this hot deal, be sure to get there EARLY!